The present invention relates to a timepiece, such as a clock or watch, of the analog type.
The search for a novel design for timepieces often results in decorative designs in which the height of the hands or the dial marks have become so inconspicuous that it is difficult to tell the time. Moreover, traditional timepieces have an hour hand which makes one revolution in twelve hours, and because it is impossible to distinguish the morning hours from the evening hours persons obliged to move from place to place quickly and cross a large number of time zones can make mistakes.
The object of the invention is to provide a timepiece which, for the sake of simplification, will be called a "clock", even if it is an alarm clock, a carriage clock or a watch, which has a distinctly novel appearance, but is particularly easily readable and which makes it possible to distinguish the two twelve-hour periods making up a day.
To achieve this result, there are already known timepieces of the analog type (U.S. Pat. Nos. 2,011,517; 2,785,530; CH-A-7021/69 and DE-U-87.01135), in which the time display means comprise two coaxial disks which are split radially and bent helically and which are arranged in such a way that each passes between the leading edge and the trailing edge of the other, leading and trailing being defined in relation to the clockwise direction of rotation.
A mechanism causes a first disk to rotate in the clockwise direction, while second is retained by a stop, the rotation continuing over one revolution from he first moment when the two disks are superposed, only one being visible, up to a second moment when the two disks are once again superposed, the only one visible at the start being concealed by the other, at this second moment the mechanism effecting an exchange in which the disk driven until then becomes retained and the disk retained until then becomes driven.
Despite the fact that some of the documents mentioned are relatively old, this system has not yet been developed, probably because of the complication and/or fragility of the mechanisms.
The object of the present invention is to provide a timepiece of the abovementioned type, but in which the mechanism for the drive and exchange of the disks is simpler, more robust and more reliable than what has been provided hitherto.